This section is intended to introduce the reader to various aspects of art, which may be related to the present embodiments that are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.
Many advanced signal receiving devices, such as set top boxes and gateways, include more than one tuner. The use of multiple tuners for tuning and receiving multiple channels simultaneously in a signal receiving device allows for a number of new features that enhance the user's home video experience. These features include, but are not limited, to multi-room playback, multi-program simultaneous recording, and remote or networked viewing options. The requirements for expansion of features associated with tuning and receiving multiple channels, such as the above, often include an ever increasing number of tuners.
However, the use of multiple tuners creates problems associated with signal routing and processing, particularly in the Radio Frequency (RF) signal processing. These problems are further complicated by the use of System on Chip (SoC) integrated circuits (ICs) that incorporate many of the necessary features used as part of a signal receiving device. Expansion of the functionality of these SoCs may prove problematic particularly as the number of tuners in the signal receiving device increases. In one example, a design having a total of six tuners may further include one or more of the RF signal interfaces requiring a differential signal input to the SoC as well as differential outputs from the SoC to drive external tuner ICs with dual integrated tuners, also requiring differential signal inputs.
The design and use of a single-ended unbalanced (i.e., non-differential) RF signal splitter is common in signal receiving systems. However, the additional requirements for operation of signals using differential input and output signaling formats present design challenges. Operation of differential signals that operate over a wide frequency range, such as a frequency range of 950 Megahertz (MHz) to 2,150 MHz, further complicates the design. Some approaches have focused on developing a differential signal splitter based primarily on the use of electromagnetic coupling mechanisms, such as transformers. However, differential signal splitters using electromagnetic coupling mechanisms are often complex, expensive, and may not be easily manufactured. Therefore, there is a need for a simple and cost effective apparatus for interfacing an RF input signal to more than one receiving circuit in a balanced differential signaling format.